Hot-air furnace.



PATENTED MAY 7, 1907. J. L. BERGER.

HOT AIR FURNACE. i

APPLIGATION FILED JUNE 12. 1905.

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""f' DRAPTQM A N- PATENTBD MAY 7, 1907.

J. L. BERGER. HOT-AIR FURNAGE. APPLICATION FILED .umn 12. 1905.

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UNITED STATES PATEET, OEEIOE.

JOHN L. BERGER, OF DENVER, COLORADO, AssiGNoR OE ONE-'WU'rn Toy GEORGE ANDERSON, OF DENVER, COLORADO.

HOT-AIR AFURNAGE.

Specification of Letters Patent.

' ratentea may 7,1907.

Appi'ieation filed June 12, 1905. serial No. 264,760.

companying drawings, and to the letters andigures of reference marked thereon, which form a part of lthis specification.

My invention relates to improvements in hot air furnaces, my objectbeing to utilize to the best advantage the .heat from the iire box, to the end that the maximum saving may be made thus economizing fuel. I accomplish. this by a construction having an increased heat radiating surface exposed to the air to be heated, as compared with furnaces of ordinary construction.f`

Having briefly outlined my improved construction as Well as the functlon it is intended to perform, I will proceed to describe the same in detail reference being made to the accompanying drawing in which is illustrated an embodiment thereof.

In this drawing, Figure 1 is a vertical longitudinal section taken through the furnace on the line 1-1 Fig. 2. Fig. 2 is a horizontal section taken on the line 2-2 Fig. 1. Fig. 3 is a detail sectional view upon an enlarged scale showing one of the tubes employed.

.4 is a sectional view of a part of the furnace illustrating a modified form of construction.

Attention is called to the fact that in Figs. 1, 2 and 4 of the drawing, the dotted arrows indicate the course of the products of combustion, while the full line arrows indicate the course of the air to be heated.

The same reference characters indicate the same parts in all the views.

Let the numeral 5 designate the outer cas- 'ing of the furnace; 6 the Ere box; 7 the grate and 8 the ash pit.

Mounted above the fire box and supported thereby is a chamber 9 having an annular space 10 communicating by short pipes 12, with a space 13 for the air tobe heated, the space 13 being located between the casing 5 and the fire box. The space 10 has no communication with the products of combustion/from the fire box. The lower part of the chamber 9 is provided with a circular inclined plate 1'4 havvw, T

ing Openings communicating with the pipes 12, thesaid plate being formed integral with the pipes. grooved` to receive the lower edge of th-e wall of a chamber 15 surrounding the chamber 9, the latte-r being located in the lower part of the chamber 15. chamber 9, is provided with openings which register with vertically disposed pipes 16,

whose upper extremities pass through openings formed in the top wall of the chamber 15. The air to be heated after entering the annular chamber 1 0, passes through the pipes 16, and thence into the upper part of' the air space surrounding the chamber 15, and thence out of the openings 17 to the hot air distributing conduits (not shown). The pipes 1 6 are suitably connected with the chamber 9 in order to form tight joints, whereby communication between the products of combustion and the air to be heated is prevented.

As shown in the drawing the two chambers S) and 15, are provided with apertured ears 18 and 19 respectively, through which are passed bolts 20. A suitable quantity of packing material designated 21, is placed in the groove-in the upper edge of the plate 14, in order to form a tight joint. The top and side walls of the chamber 15 are con nected by means of bolts 22 or other suitable fastening devices.

From the foregoing description the use of the furnace as thus far described will be readily nnderstood. The-heatand products of combustion from the fire box, pass upwardly Within the chamber 15, surrounding the chamber 9 and the pipes 16, the products of combustion finally escaping through the smoke flue 24. It will thus be seen that by reason of the chamber 9 and the pi es 16 (the latter forming a multiple tube con uit for the air to be heated,) there is a considerable surface area exposed to the action of the heat. The air to be heated entering through the cold air duct 25, irst passes to the space 13 between the casing 5 and the fire box, thence through the short pipes 12 to the space 10 of the chamber 9, and thence through the tubes 16 to the hot air space above the chamber 15. The air to be heated also passes around the The top of the annular The upper edge of the plate isnti'o'Y TOO chamber 15, as well as through the chamber 9 and the tubes 16, presenting a very extensive heat radiating surface to the air, the object being as aforesaid to utilize the heat from the fire box to the best advantage, and reduce the temperature of the products of combustion to the lowest practicable degree before allowing them to escape to the smoke flue.

In the form of construction shown in Fig. 4, a single conduit 26 is located within the chamber 15 and connected with the chamber 9. In this view is also shown a hollow core 27 located within the large tube 26, this hollow core being closed at the top and open at the bottom to the products of combustion. This hollow core 27 may be used or not as desired. If it is not used of course some other means must be employed to close the central opening 28 through the chamber 9, in order to prevent the products of combustion from thefire box from mingling with the air to be heated. to be heated enters the chamber 9 in the same manner as heretofore explained, and passes thence up through the tube 26, as well as around the chamber 15; while the products of combustion from the fire box, pass upwardly into the chamber 15 around the large tube 26 and finallyvl out through the smoke ipe 24. These products of combustion also enter the hollow core 27 when the latter is employed. This tube 27 presents additional heat-radiating surface to the air passing through the tube 26.

The upper part of the chamber 9, is preferably downwardlyT inclined in both directions as shown in Fig. 1 in order to prevent the accumulation of soot-or dirt, upon the top of the said chamber. By reason of these sloping sides as indicated at 9, the soot, dirt and ot er material, which otherwise would have a tendency to lodge upon the top of the chamber 9, readily slip downwardly therefrom and enter the fire box.

In further explanation of the connection between the tube 16 and the chambers 9 and 15, it may be stated that the lower extremity of each tube 16 is surrounded by a collar A fastened to the circular apex 9a of the chamber 9. The lower part of the tube within the collar A is provided with a circular rib B which is so located as to occupy a position about midway of the height of the collar A. The space between the lower extremity of each tube I16 and the collar A is filled with a suitable packing material C for the purpose of making a perfectly tight joint. The upper extremity of each tube 16 is threaded exteriorly as shown at D where it passes through an opening formed in the top of the chamber 15. This tube is connected with the top wall In this form of construction the air of the chamber 15 by means of nuts E and F applied to the tube above and below the top plate of the chamber. The upper interior corner of the nut Fis cut away to make room for a quantity of packing material G which in connection with the washer II forms a tight joint around the tube.

Having thus described my invention, what I claim is:

1. In a hot air furnace, the combination with a re box, of a products-of-combustion chamber located above vthe iire box, an air chamber interposed between the productsof-combustion chamber and the fire box and having a circular apex at its top provided with openings, collars surrounding said openings, tubes whose lower extremities enter the collars, means for forming an air tight joint between the tubes and the collars, the top of the products-of-combustion chamber being provided with openings to receive the upper extremities of the tubes whose ends are threaded, nuts applied to the threaded extremities of the tubes above and below the top of the products-of-combustion chamber, and means for forming an air tight joint between the threaded extremities of the tube and the top of said chamber.

2. In a hot air furnace, the combination with an outer casing and a re box, of a products-of-combustion chamber located above the fire box, an air chamber interposed between the fire box and the products-of-combustion chamber, the air chamber being formed at the top with an apex whose downwardly sloping sides are considerably inclined, the said apex being provided with openings, tubes whose lower extremities register with said openings, the top of the products-ofcombustion chamber having openings to receive the upper extremities of the tubes, and suitable means for formin air tight joints between the tube extremities and the parts with which they are connected.

3. In a hot air furnace, the combination with an outer casing and a fire box, of a products of combustion chamber located above the'iire box, an air chamber interposed between the fire box and the products of combustion chamber, the air chamber being formed at the top with an apex whose downwardly sloping sides are considerably inclined, the said apex being provided with openings, and tubes whose lower extremities register with said openings.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN L. BERGER.

Witnesses GEO. ANDERsEN, A. J. OBRIEN.

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